Synchronous Optical Networks ("SONET") represent a new generation of telecommunications networks and the collection of standards for network architectures and protocols. Coinciding with the rollout of new SONET networks is the development of SONET network management systems. A network management system ("NMS") is used to monitor a telecommunications network, provide status on the state of the network, and provide control over the network to resolve problems such as outages and traffic congestion. Control is provided in the form of commands issued to the network and responses received from the network.
FIG. 1 illustrates a very simplified architecture of a SONET network 50 connected to a Network Management System 75 via a WAN 65 implementing a TCP/IP communications transport protocol. A typical SONET network consists of thousands of network elements 60 and mediation devices 70 interconnected in many various configurations. A non-exhaustive list of network elements include the following types of telecommunications networks, services and equipment: digital and analog transmission systems such as cable, fibre, radio, satellite, etc; restoration systems; re-generation systems and termination equipment; public and private networks including both narrow and broadband ISDNs, mobile networks, etc; transmission terminals such as multiplexers, cross connects, channel translation equipment; operations systems and their peripherals; mainframe computers; front-end processors; file servers; area networks, e.g., WAN, LAN etc.; circuit and packet switched networks; and PBXs. Mediation devices 70 are used to concentrate several network elements at a single network address and additionally buffer messages sent from network elements 60 to the NMS 75. As shown in FIG. 1, one or more network elements can be connected to a mediation device.
In operation, each of the above-mentioned network elements autonomously send event messages, such as alarms, to the NMS over the TCP/IP WAN. In a typical network, the NMS may receive 2 alarms/second from 10,000 network elements in steady state operation, and 100 alarms/second in burst modes. The network elements also receive commands from the NMS including, for example, audit requests, provisioning requests, state requests, and switching commands. The network elements must then formulate response messages and send them to the NMS. These messages (both solicited and unsolicited) are typically formatted in accordance with an industry standard known as TL-1.
Prior to placing a new or modified NMS in production, the NMS must be thoroughly tested. Testing generally consists of three types: 1) functionality testing to ensure that the NMS meets the functional requirements; 2) stability testing to ensure that the NMS performs uniformly under the same conditions, and in response to the same activity being repeated; and 3) stress testing to ensure that the NMS performs as expected under conditions of high volumes of messages to and from the network.
Additionally, the users of the NMS would require proper training on the operation and use of the new or modified functions of the NMS.
Current testing techniques require that the NMS be connected to a test tool that simulates network elements, i.e., receive commands from the NMS and provide responses, as well as send unsolicited messages, such as simulated alarms, to the NMS. While functionality and stability testing may be performed easily with a simple tool that simulates one or a few network elements, stress testing requires simulation of an actual network requiring the generation of very large volumes of messages in order to simulate the thousands of network elements of a dozen or more types that constitute a typical SONET network. In addition, the test tool must support thousands of logical connections to the NMS, to represent the individual connections of each network element it is simulating.
Network simulators currently available cannot support the high volumes of message processing from the variety of network element types needed to simulate a large SONET network.